Plate cylinder for printing presses and stereotype plates



2 Sheets-Sheet l F. A. FOSTER Filed July 25, 1954' mw, w

f ORNEYS PLATE CYLINDER FOR PRINTING PRESSES AND STEREOTYPE PLATES July 14, 1936.

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July 14,1936.

F. A.- FOSTER Filed July 25, 1934 2 Sheets-Sheet 2 INVENTOR Patented July 14, 1936 UNITED f STATES VPLATE CYLINDER FOR PRINTING PRESSES AND STEREOTYPE PLATES Frank A. Foster, Maywood, Ill., assigner to The Goss Printing Press Company, Chicago, Ill., a

corporation of Illinois Application July 25, 1934, Serial No. 736,816

11 Claims. (Cl. 101-3'18) The invention relates to rotary printing presses and more especially to new and useful improvements in means for holding stereotype plates and 'the like on the plate cylinders of rotary presses.

Objects and advantages of the invention'will be set forth in part hereinafter and in part will be obvious herefrom, or maybe learned by practice with the invention, the same being realized and attained by means of the lnstrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations and irnprovements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention.

Of the drawings:

Fig. 1 is a plan view, with parts broken away, of the plate cylinder of a printing press;

Fig. 2 is an enlarged sectional view taken on the line 2 2 of Fig. l;

Fig. 3 is a detached perspective view of the actuating slide for the plate-engaging means;

Fig. 4 is a similar View of the device for engaging with and tensioning the plate;

Fig. 5 is an enlarged part sectional view taken on the line 5-5 of Fig. 2;

Fig. 6 is a like view taken on the line 6--6 o1' Fig. 2; and

Fig. 7 is a fragmentary sectional View oi' a stereotype plate adapted to be used with the illustrated type of plate cylinder.

One object of the invention is to provide plateholding means which hold the plate to the. cylinder by applying thereto means and forces which operate most favorably to eliminate and to minimize the forces and conditions which during printing tend to dislodge, deform or destroy heavy rigid plates mounted on high-speed cylinders. In. connection with the object just stated the invention further provides simple, sturdy, exact, resilient and easily operated means for engaging, holding and releasing stereotype plates `upon a printing cylinder. Manycommerciallyusedplate-holding devices exert opposed clamping or compression strains on the plate, especially inwardly from the 50 arcuate edges thereof, tending to force or buckle the plate centrally, this type of pressure or strain being necessarily increased as the press speed increases and therewith the centrifugal action upon the plates. Such plate-holding devices, and 55 others known to the art, exert-rigid strains, either compressive or tensiona'l, which fail to compensate for the powerful, quickly acting and rapidly changing strains incident to fast rotary printing,

i and which .tend either to dislodge, deform or diS- 60 rupt the plate.

The present invention obviates the tendency to dislodge the plates which is created by the impact against the leading edge of the plate of the squeeze between the plate cylinders, and also avoids the tendency to centrally buckle the plate 5 which is created by clamps applied to the arcuate edges of the plate. The invention also eliminates the tendency to deform or buckle the plate lengthwise, which normally arises from the rolling or traveling of the printing squeeze along the plate, the repetition of which action results in uneven printing from different parts of the plate'and eventually often results in breakage of the plate. With the attainment of these objects in view, all inwardly directed pressures on the arcuate edges of the plate are avoided, and holding means are applied to the leading edge of the plate to hold it radially to the cylinder and to positively and directly oppose the substantially tangential component ofthe impact of the impression cylinder against the head of the plate. At the same time there is imposed on the trailing end of the plate a live resilient tension throughout the length of the plate, which holds the plate firmly and powerfully about the cylinder and likewise furnishes a live resilient tension between the trailing end of the plate and the line of impression squeeze g as it moves swiftly along the plate.

Further objects and advantages of the invention Will be set forth in connection with the subsequent detailed description of the presentpreferred embodiment, and it will be understood 'that the precedinggeneral statement and the following detailed description are bothexemplary and illustrative and not restrictive'oi the f invention. n

Referring to the preferred embodiment oi' the invention, illustrated by way ofjexample in the accompanyingl drawings, the invention is shown applied to a plate cylinder adapted to take one stereotype plate around, but it willA be `under-- stood that inmost of-its features `the 'invention is equally applicable to plate cylinders for taking two or more plates around. Referring lnow in detail to said preferred embodiment, a plate cylinder I is shown having shaft members 2 and 3 upon` which the plate cylinder is journaled in the press. In the present preferred embodiment, the plate holding and tensioning means are shown adapted to hold a plate having lockup lugs orprojections, disposed longitudinally near the leadingand trailing ends of the plate, and extending inwardly from the interior surface of the plate. These lockup lugs on the plates are adapted to engage with the devices on, or rather within the cylinder to hold and tension the plate about the cylinder, although in many of Vits "features the present invention is adapted to hold and tension otheriorms of plates.

A stereotype plate of the kind referred to is 60 shown fragmentarily in Fig. 'I of the drawings, and the plate is further exemplarily shown of the type wherein a single plate encompasses almost the entire cylinder, leaving only a gap sufficient to pass the cylinder supports when the plate is inserted on or removed from the cylinder longitudinally. Plate 1 has its printing surface at 3, and is provided on its inner cylindrical surface with longitudinally disposed, spacedapart ribs 9, which are in effect elements of a cylindrical surface, and rest on the surface of the plate cylinder I to support the plate in position thereon. The ribs are beveled'slightly in cross-section from their roots inwardly to the edges of the ilat or slightly arcuate inner surface thereof (as shown in Fig. 7), and the at inner surface of each rib is beveled longitudinally from one end to the other, so that the cast plate may be readily withdrawn lengthwise from the core of a casting machine.

Longitudinally disposed lockup'lugs or bars I0 and II are provided near the leading and trailing ends of the plate, as already indicated, and are adapted to engage with the plate-holding and tensioning devices later to be described. The lookup lugs are shaped and positioned to tension the plate resiliently about the cylinder, to prevent radial displacement of the plate, and also to prevent tangential or circumferential displacement of the plate. To this end they projectl inwardly diagonally, as shown in Fig. 7, that is, they have their operating faces disposed at an angle and not radially. (Fig. '7.) The ribs 9 and lookup bars III and II are preferably formed with a slight bevel on all of the projecting faces, the purpose of the bevels being to` permit the plate to be readily removed longitudinally from the core of the casting machine. After the plate is removed from the casting machine, it is placed in a broaching machine and the inner face of the ribs, which form the bearing surface on the plate cylinder, are broached down to the proper plate thickness throughout their length. The

lockup lugs or bars are also finished so that theI lockup faces are parallel with the axis of the plate.

Referring now to the embodiment of the plateholding and tensioning means, they are shown exemplarily applied to a plate cylinder holding one plate around and two plates along, and to a plate of the kind :lust described. As so embodied, the means for holding the leading straight end of the plate on the cylinder I comprises a diagonally inclined, undercut, longitudinally disposed groove I1, shaped so that the lookup lug or bar I0 formed on the inner side of the leading end of plate 'I may be slid longitudinally into the groove I 'I, as the plate goes on the cylinder. The projection and groove are shaped so that the leading edge of the plate is thus positively held against displacement either radially, circumferentially or tangentially although the holding means in itself does not exert any strain upon the plate.

The tension which is placed upon the plate t0 stretch and hold it closely about the cylinder is preferably exerted through the means engaging the trailing end of the plate acting on the plate as it is held by the lookup lug at the leading end of the plate. Such means may be arranged not only to exert live tension on the entire plate from the holding means at the leading end to the trailing end, but also to exert a live tension between the traveling line of the printing squeeze which is exerted between the plate cylinder and impression cylinder, as it sweeps along the plate from the leading end thereof towards the trailing end. Means are further provided by the invention for imposing both a positive tension and a concurrent and cooperating resilient tension on the trailing end of the plate to strain the entire plate to yand about the cylinder. As embodied (Figs. 1, 2, 5 and 6) an inverted T slot I9 is formed within and longitudinally of the plate cylinder I, within which the plate-holding and tensioning means is positioned and operates. An actuating bar 20 extends along and rests on the bottom of the slot I9, and is slidable longitudinally therein to move the devices which engage the stereotype plate into and out of tensioning relation to the plate. This longitudinal movement of the actuating bar 20 is manually effected and provides a very positive and accurate control of the plate-holding and tensioning means. As embodied, at the left-hand end in Figs. 1 and 2, actuating bar 20 has an upwardlyextending projection 23, into which is screwthreaded a bolt 24, which is mounted to rotate in a plate 25, xed to the end of the cylinder, but is held against longitudinal movement lby collars 26 and 21 fixed to the bolt on either side of the plate 25. '-Ihe screw rod 24 has a squared head, and by turning rod 24 a very fine and accurate movement of the actuating slide 20 and of the plate-engaging means controlled thereby may be effected.

The embodied form of plate-engaging and tensioning means actuated and controlled by the slide 20 comprises an engaging piece 29, which rests upon actuator bar 20, and at its bottom part (Fig. 5) it extends laterally beneath the overhanging parts of T-slot I9 (Figs. 1, 2, 4 and 5).

It has a cut-out and undercut portion 30 adapted to pass behind and above the undercut, longitudinally-disposed lookup lug II on the stereotype plate. With this form of plate, the mechanism just described is within the slot I9, the ribs 9 of the plate resting upon the surface of the cylinder. The actuating connections between the plate-engaging means 29, 30 and the actuating bar 20 (Figs. 1. 2 and 5), comprise one or more rollers 34 beneath the plate-engaging and tensioning member 29, and journaled on pins 35 tted within recesses in the underside of the member 29. The rollers 34 project into diagonally-disposed slots 39 formed in blocks 3I set loosely in recesses 38 formed in the actuating bar 20. The blocks 31 are normally resiliently impelled toward one end of the recesses 38, as by springs 40 seated in recesses 3B' in the actuating bar (Figs. 1 and 2). For the purpose of holding the foregoing structure in position in the slot I9, there are provided in spaced-apart relation pairs of clips 4I (Figs. 1 and 6) set into recesses formed in the cylinder and extending over the actuating bar 20 to hold it in position. The plate-engaging member 29 is recessed at each of the holding clips, as shown at 42, to permit lateral movement thereof to tension and to release the plate. The clips 4I are held in position by screws 43 threaded into the cylinderI I.

In accordance with one feature of the invention, and as exemplarily shown in the drawings. a plurality of plates are shown along the cylinder with a single actuating means for the plate-locking and tensioning device. In connection therewith, as embodied, means are provided (Figs. 1 and 2) whereby the relative longitudinal position of two actuating bars 20 may be varied and regulated, which provides a separate regulation for the tension exerting action on the respective plates with the use of one controlling means for the actuating bars. As embodied, the left-hand actuating bar 20 is provided at its inner end with an upwardly-pro-I jecting lug 41 and the right-hand actuating bar 20 is provided at its left-hand end with an upwardly-projecting lug 48. Screw-threaded by right and left hand threads into the lugs 41 advantages.

and 48 is a screw rod 49 having a turning head 50. By turning the screw 49 the relative position of the cam blocks 31 in the two actuating bars may be varied and a corresponding difference eiected in the movement of the corre` sponding plate-engaging and tensioning devices 29.

In the operation of the mechanism, the screw 24 is turned so that the jaw 30 will be behind lockup lug I las the plate is slid onto the cylinder. 'I'he screw 24 is then turned in the reverse direction, moving the actuating bar 20 longitudinally in slot I9, and by reason of the inclination of the cam slots 39, the plate-engaging and tensioning member 29 is moved laterally and jaw 30 engages behind and over lookup lug Il, pressing against it both to hold the trailing end of the plate' against radial displacement, and at the same time placing the plate under tension about the cylinder and pressing it closely to the cylinder throughout its area. At the same time the springs 40 are put under tension, and these give a live, resilient tensional pull upon the plate at all times. They equalize the tension at spacedapart points along the trailing end of the plate. Ii there is any tendency of the plate to stretch or of the plate-engaging member to become embedded in the lug Il, the springs 4I! back of the cam blocks 31 will'either compress or expand as may be required to hold the plate-engaging member in contact with the plate or to permit relative yield at a particular point, while at the same time exerting the required tension.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacriilcing itschief What I claim is: Y

1. In combination, a stereotype plate cylinder, means engaging a stereotype plate adjacent both straight ends to .tension the plate about the cylinder, the means at one straight end ineluding mechanism for positively tensioning the plate and a cooperating resilient tension-producing device for further tensioning the positively tens'ioned plate.

2. In combination, a stereotype plate cylinder, means engaging a stereotype plate adjacent both straight' ends to tension the'plate about the cylinder,'the means at one straight end including manually operated mechanism for positively tensioning the plate and a cooperating resilient tension-producing device for further tensioning the positively tensioned plate. v

3. In combination, a stereotype plate cylinder, means engaging a stereotype plate adjacent both straight ends. to tension the plate about the cylinder, the means at one straight end including mechanism for positively moving a plate-en- Vgagingdevice to tension the plate-and auto- 4. In combination, a stereotype plate cylinder, means engaging a stereotype plate adjacent both straight ends totension the plate about the cylinder, the means at one straight end including mechanism for positively tensioning the plate at 5 separated points on said straight end and cooperating resilient tension-producing mechanism act-` ing at separated points on said straight edge.

5. Inv combination, a stereotype plate cylinder, means engaging a stereotype plate adjacent both straight ends to tension the plate about the cyl. inder, the means at one straight end including mechanism for positively tensioning the plate at separated points on said straight end and cooperating resilient tension-producing mechanism l5 acting automatically at separated points on said straight edge. K

6; In combination, a stereotype plate cylinder, means engaging a stereotype plate adjacent both straight ends to tension the plate about the cylin- 20 der, the means at one straight end including a plurality of `spaced apart plate-engaging members, means for positively moving said members to tension the plate and resilient cooperating tension-producing means.

7. In combination, a stereotype plate cylinder, means engaging a. stereotype plate adjacent both straight ends to tension the plate about the cylinder, the means at one straight end including a plurality of spaced apart plate-engaging mem- 30 bers, mechanism for positively moving said mexnbers to tension the plate and aplurality of resilient tension-producing devices cooperating with the respective plate-engaging members.

8. In combination, a stereotype plate cylinder, 35 means engaging a stereotype plate adjacent both straight ends to tension the plate about the cylinder, the means at one straight end including a plurality of spaced apart plate-engaging members, mechanism for positively moving all said members to tension the plate and a plurality of resilient tension-producing devices automatically cooperating with the respective plate-engaging members.

V9. In combination, a stereotype plate cylinder, means engaging a stereotype plate adjacent both straight ends to tension the plate about the cylinder, the means at one fixed end including a plurality o! circumierentially movable plate engaging members and an axiallly movable member coacting therewith for moving said engaging members to tension the plate, and resilient meansl for further moving said engaging members during the printing operation. Y

10. In combination, a stereotype Plate cylinder. means engaginga stereotype plate adjacent both straight ends to tension the plate about the cylinder, the Vmeans at one ilxed end including a plurality ot circumferentially movable plate engaging members and an axially movable resilient 60 means acting on said members to move said members during the printing operation to maintain the plate under circumferential tension.

1l. In combination, a stereotype plate cylinder, means engaging a,stereotype plate adjacent both 05 straight ends to tension the plate about the cylinder, the means at one ilxed end including a pluralityfofl circumferentially movable plate engaging members and an axially movable resilient means acting on said members with a wedging 'action to move said members as the plate is stretched while printing to maintain the plate. under circumferential tension. i

l FRANK A. FOSTER. 

